Understanding Computer Security

Learn how to protect your PC from viruses

When you buy a car, it has certain safety features built in. After you drive it off the lot, you might find that the manufacturer slipped up and either recalls your car or requests that you go to the dealer's service department to get a faulty part replaced. In addition, you need to drive defensively to keep your car from being damaged in daily use.

Your computer is similar to your car in terms of the need for safety. It comes with an operating system (such as Microsoft Windows) built in, and that operating system has security features. Sometimes that operating system has flaws, and you need to get an update to keep it secure. And as you use your computer, you're exposing it to dangerous conditions and situations that you have to guard against.

Threats to your computer security can come from a file you copy from a disk you insert into your computer, but most of the time the danger is from a program that you downloaded from the Internet. These downloads can happen when you click a link, open an attachment in an e-mail or download a piece of software without realizing that the malware is attached to it.

— Darren Greenwood/Design Pics/Corbis

There are three main types of dangerous programs (called malware) to be aware of:

A virus is a little program that some nasty person thought up to spread around the Internet and infect computers. A virus can do a variety of things, but typically it attacks your data, deleting files, scrambling data or making changes to your system settings that cause your computer to grind to a halt.

Spyware consists of programs whose main purpose in life is to track what you do with your computer. Some spyware simply helps companies you do business with track your activities so they can figure out how to sell you things; other spyware is used for more insidious purposes, such as stealing your passwords.

Adware is the computer equivalent of telemarketing phone calls at dinner time. Once adware gets downloaded onto your computer, you'll get annoying pop-up windows trying to sell you things all day long. Beyond the annoyance, adware can quickly clog up your computer, so its performance slows down, and it's hard to get anything done at all.

To protect your information and your computer from these various types of malware, you can do several things:

You can buy and install an antivirus, antispyware or anti-adware program. Programs such as McAfee Antivirus, Norton Antivirus from Symantec or the freely downloadable AVG Free from Grisoft can help stop the downloading of malicious files, and they can detect files that have somehow gotten through and delete them for you. Remember that after you install such a program, you have to get regular updates to it to handle new threats, and you need to run scans on your system to catch items that might have snuck through. Many antivirus programs are purchased by yearly subscription, which gives you access to updated virus definitions that the company constantly gathers throughout the year.

Programs such as Norton Antivirus from Symantec can help stop the downloading of malicious files, and they can detect files that have somehow gotten through and delete them for you.

Some other programs such as Spyware Doctor from PC Tools combine tools for detecting adware and spyware. Windows 7 has a built-in program, Windows Defender, that includes an antispyware feature.

You can use Windows tools to keep Windows up to date with security features and fixes to security problems. You can also turn on a firewall, which is a feature that stops other people or programs from accessing your computer without your permission.